A technique of mounting an in-wheel motor inside a wheel of an electric vehicle to drive the wheel by the in-wheel motor is conventionally known in the art. In such electric vehicles, it is not necessary to mount an engine and a motor on a vehicle body, which is advantageous in that the vehicle body can have larger internal space such as passenger space and cargo space. The in-wheel motor is coupled to the vehicle body of the electric vehicle via a suspension device. A control unit, a battery, and an inverter for the in-wheel motor are mounted on the vehicle body. The in-wheel motor coupled to an unsprung part (the wheel side) of the suspension device and the inverter mounted on a sprung part (the vehicle body side) of the suspension device are connected by power lines. For example, power lines as described in Japanese Patent No. 4,628,136 (Patent Literature 1) and Japanese Unexamined Patent Application Publication No. 2006-240430 (Patent Literature 2) are conventionally known as power lines that supply electric power from the inverter to the in-wheel motor. The power lines described in these patent literatures are attached to an upper arm of the suspension device by a clamp member or are attached to the in-wheel motor by a clamp member.